This project consists of neurophysiological and neuroanatomical investigations of the organization of the somatic sensorimotor cortex and its role in the control of primate motor behavior. One of the central questions concerning the organization of the cerebral cortex is how inputs to a cortical region from cortical and subcortical sources combine to contribute to its output. We have chosen to concentrate on the precentral motor cortex (MI), known to project directly to spinal motor neurons, and those cortical areas in close functional association with MI, the supplementary motor cortex (MII); area 3a (a transitional region between MI and the postcentral somatic sensory cortex), and the premotor cortex (area 6). Two related approaches have been adopted for this project: (1) an analysis of the organization of peripheral inputs to the premotor cortex, MI, MII and area 3a and (2) single unit studies of cortical areas which supply inputs to MI. In the past year, we have concentrated on to premotor cortex and its activity in relation to planned movements and their execution.